I've never shot a Phantom, but it looks like a typical 62" recurve. One of the problems with Samik is that they are vague about brace height. Any other recurve you buy will have fairly specific recommendations for brace height; e.g 8 1/4 - 8 1/2, a 1/4" range. As many bows as Samik is selling now in the US, you would think they would do some testing of their own and narrow down the range a little. A range of 8 1/4 - 9 1/4 is a joke. Samik makes pretty good bows, but this kind of thing doesn't help them any.
I have two Samiks, a Red Stag and a Night Hawk, which I haven't extensively tested for brace height, as they are intended for use by grandchildren or in classes I teach, although I have managed to get good bare shaft flight out of both at the mid-point of their recommended brace height ranges.
The 8 1/4 - 8 3/4 range that I posted came from Lancaster, which is a major distributor of Samik bows in the US. They have sent representatives to Samik in Korea and vice versa to help get the brand established in the US. That doesn't make them right, necessarily, but they do have a commitment to Samik bows.
If you twist up the string to where there are more than two twists per inch, you should consider getting a shorter string. I can't tell you if 7 3/4 is the right place, only that it's a little lower than I am using on my other Samik bows.